Header of heat exchanger and heat exchanger provided with the same

Abstract

A header of a heat exchanger including a first wall connected with a plurality of heat transfer tubes of the heat exchanger, a second wall facing the first wall with an interval therebetween, and a circumferential wall connecting outer circumferential edges of the first and the second walls in such a manner that an area between the first and the second walls constitutes a chamber for inflow of fluid, the chamber communicating with each of the heat transfer tube. At least one of the first and the second walls is configured to curve in such a manner that a central area of the wall is positioned close to an inside of the chamber than an outer circumferential area of the wall. The thickness of the header is reduced and enough strength of the header is obtained, thereby preferably enduring repeating water hammer.

The invention claimed is: 
     
       1. A heat exchanger comprising:
 a plurality of heat transfer tubes; 
 a case having a main body and a side wall, wherein the side wall blocks an opening of an end of the main body, the case housing the plurality of heat transfer tubes; and 
 a header configured to enter water into the plurality of heat transfer tubes or to deliver heated water from the plurality of heat transfer tubes, 
 wherein 
 the side wall of the case is partially provided with a bulging portion being formed on a part of the side wall, wherein the side wall departs from a joined portion of a peripheral portion of the side wall and the main body, the bulging portion having a cylindrical wall bulging out of the case and a tip end wall, wherein the tip end wall is integrally connected to the cylindrical wall so as to block a tip portion of the cylindrical wall and wherein the tip end wall has a plurality of penetrating holes, 
 the cylindrical wall and the tip end wall are integrally provided with the side wall, and the part of the side wall is bulged from another area of the side wall, ends of the plurality of heat transfer tubes are inserted into the penetrating holes, respectively, and are joined with the tip end wall, 
 the header has an auxiliary member including a hollow main body having an open edge forming an opening corresponding to the bulging portion and the opening is blocked by the tip end wall by fitting the open edge onto the cylindrical wall, thereby a chamber communicating with the plurality of heat transfer tubes is formed in the header, and 
 a whole of the tip end wall is configured to curve along a first axis of the header and along a second axis of the header, the first axis being perpendicular to the second axis, such that a central area of the tip end wall is positioned closer to a center of the chamber than an outer circumferential area of the tip end wall. 
 
     
     
       2. The heat exchanger as set forth in  claim 1 ,
 wherein the hollow main body having an opposite wall facing the tip end wall via the chamber, a whole of the opposite wall is configured to curve in such a manner that a central area of the opposite wall is positioned closer to the center of the chamber than an outer circumferential area of the opposite wall. 
 
     
     
       3. The heat exchanger as set forth in  claim 1 ,
 wherein the side wall of the case comprises a metal plate, and 
 the bulging portion is integrally formed with the side wall by a press-working. 
 
     
     
       4. The heat exchanger as set forth in  claim 1 ,
 wherein each of the plurality of heat transfer tubes comprises a helical tube body or a meandering tube body, 
 the case has a supply port receiving heating gas and a discharge port discharging heating gas, and 
 the heating gas flowing in the case from the supply port flows out of the case from the discharge port after flowing through the tube body. 
 
     
     
       5. The heat exchanger as set forth in  claim 2 ,
 wherein at least one of the tip end wall and the opposite wall is provided with at least one protruding portion partially protruding into an inside or an outside of the chamber. 
 
     
     
       6. The heat exchanger as set forth in  claim 5 ,
 wherein the protruding portion protrudes into the inside of the chamber. 
 
     
     
       7. The heat exchanger as set forth in  claim 5 ,
 wherein the protruding portion comprises a protruding portion provided between connection portions of the plurality of heat transfer tubes on the tip end wall. 
 
     
     
       8. The heat exchanger as set forth in  claim 5 ,
 wherein the plurality of heat transfer tubes are connected to the tip end wall so as to be arranged in a fixed direction, and 
 the protruding portion comprises a protruding portion provided at a position of the tip end wall being offset in a direction intersecting the fixed direction relative to the connection portions of the plurality of heat transfer tubes, the protruding portion being configured to be elongated in the fixed direction. 
 
     
     
       9. The heat exchanger as set forth in  claim 1 ,
 wherein the heat exchanger comprises a pair of the headers. 
 
     
     
       10. The heat exchanger as set forth in  claim 1 ,
 wherein the heat exchanger comprises a pair of the bulging portions.